That's an excellent question. Because of the Chinese word "lauwai" (or laowai) in your post, I assume you have China in mind. So, as for China, it quite depends who you submit your application to. If you apply directly to a Chinese employer, be as clear and as simple as you can. However, some young Chinese administrators are at a high intermediate leve of English and they'd want to see more of a higher and pro language letter. My observation is that it is much more difficult with these "better at English" locals as their "Chinese English" expectations may not exactly meet your pro approach you are used to. Therefore, I'd go straight and simple as well as brief although a bit "EMOTIONAL" in my letter. I don't believe Chinese formal and informal appraoch is as much different as ours, but please do not shoot me for my thought here.

All the best to you
and
Cheers and beers to all